6s packs last longer than 4s?

I've read in a few posts that 6s packs run longer than a 4s pack of the same mah. For instance a 6s 5000mah pack has a longer runtime than a 4s 5000mah? I though mah was the deciding factor on runtime. Can someone explain?

[lutach]

It all comes down to the amount of AMPs used by the higher voltage of the 6S to get the same power as the 4S.

Example:

1500 (watts)/14.8 (4S)= 101A
1500 (watts)/22.2 (6S)= 67A

You will need to select the right Kv motor and gear both the same and you'll see a much more efficient and cool running set up with higher voltage set up.

[BrianG]

Yes and no.

Think of it like this: you need X amount of power to have the vehicle perform like you want. Let's say you need 250w average (fairly typical). At 4s, you need 16.89A average. With 5Ah pack, that gives you almost 18 minutes of runtime. At 6s, you need 11.26A for the same power, and that gives you 26.64 minutes or runtime.

Now, this assumes you regear to achieve the same speed in both cases, and that you aren't exceeding the max motor rpm...

[Finnster]

In addition... there is simply more total energy in the larger pack. Makes sense right as its bigger and heavier? ;) if you are pulling the same power from the pack, the one with more energy will last longer ( as briang said)

Energy= voltage*capacity (ie mah) or power*time
EG E=22.2V*5Ah= 111 Watthours (vs 14.8V*5Ah)

So to my understanding, you multiply the voltage by amp hours to get watthours and the higher the watt hours, the longer the runtime. Correct? Does this still workout the same if u run 4s with a 2700kv and the 6s with a 2000kv motor as long as u gear them for the same speed?

I'm looking for a nice 6s pack but I dont see any on mikes site??

[suicideneil]

Because most guys use a pair of 3s packs wired in series. A single 6s pack is more likely to be found in a plane or heli, than a truck, hence.